package com.kpmg.datalake.common.utils.signutils;


import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.security.MessageDigest;

/**
 * MD5工具
 * ClassName: MD5Util
 * @Description: MD5工具
 * @author yechangpeng
 * @date 2017年8月25日
 */
public class Md5Util {
	
	private Md5Util() {} 
	
	private static final Logger logger = LoggerFactory.getLogger(Md5Util.class);

	private static String byteArrayToHexString(byte[] b) {
		StringBuilder resultSb = new StringBuilder();
		for (int i = 0; i < b.length; i++) {
			resultSb.append(byteToHexString(b[i]));
		}

		return resultSb.toString();
	}

	private static String byteToHexString(byte b) {
		int n = b;
		if (n < 0) {
			n += 256;
		}
		int d1 = n / 16;
		int d2 = n % 16;
		return hexDigits[d1] + hexDigits[d2];
	}

	public static String md5Encode(String origin, String charsetname) {
		String resultString = null;
		try {
			resultString = origin;
			MessageDigest md = MessageDigest.getInstance("MD5");
			if (charsetname == null || "".equals(charsetname)) {
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes()));
			} else {
				resultString = byteArrayToHexString(md.digest(resultString
						.getBytes(charsetname)));
			}
		} catch (Exception e) {
			logger.error(e.getMessage());
		}
		return resultString.toUpperCase();
	}

	private static final String[] hexDigits = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

}
